package demo;

class Node6{
    private static Node6 a=new Node6();
    private Node6(){

    }
    public static Node6 get(){
        return a;
    }
}




class Node6s{
    private static volatile Node6s a=null;
    private Node6s(){

    }

    public static Node6s get(){
        if(a==null){
            synchronized(Node6s.class){
                if(a==null){
                    a=new Node6s();
                }
            }
        }
        return a;
    }
}



public class Demo6 {
}
